1. Field of the Invention
The present invention relates to a test facility for error diagnosis in multi-computer systems, particularly in multi-microcomputer systems, in which signal voltages on the system bus to be taken into consideration in the error diagnosis are made visible by means of display devices directly controlled by the signal voltages.
2. Description of the Prior Art
In multi-computer systems, particularly in such systems as are executed with microcomputers, it is necessary both in practical operation and in the development phase to perceive the states of all microcomputers as quickly as possible given occurring errors. Thereby, it is to be continuously clarified as to which microcomputer or microcomputers function erroneously and whether the case for an erroneous behavior is to be sought in the hardware or in the software. A significant indication for clarifying this question is supplied by considering all bus signals. Up to now, oscilloscopes, emulators and logic analyzers were available for these purposes as auxiliary structure. As is known, an oscilloscope is only slightly suitable for interpreting the bus signals of a microcomputer and an emulator is not suited at all. A logic analyzer would have to cover the full bus width (data, address, control, interrupt lines) with the plurality of its channels. In executed example of microcomputer systems, this would be approximately forty data and approximately ten trigger inputs, whereby the possibility to subdivide these inputs into three groups which operate independently of one another must exist. This existing condition, and the selection of the appropriate time grid group can make the employment of two or even three logic analyzers necessary. In addition, it involves a great deal of time to reprogram the logic analyzer for each error search. Moreover, the programming must be documented for reproducible results. Under certain conditions, this expense must be laid out for each microcomputer of the multicomputer system concerned.